Photolithography

Figure I is a plot of a test PCB, with 10 mil line width, and 10 mil spacing. It is a rectangular spiral of 2 lines, (think of an extension cord, coiled up.) Bridging and opens can be tested with an Ohm meter, (i.e., pins 1-1 should be a short, as should pins 2-2, but pins 1-2 and 2-1 should be open.) The circuit is about 10cm X 7cm, and the total run length is about 40 feet, (20 feet for each of the two lines.) The circuit was designed using gEDA's PCB program, and the archive for the circuit, 10x10.tar.gz, is available.

One of the limitations of DIY PCB's is printing the artwork-home printers have limited resolution. The circuit can be printed on various transparencies, (for exposure to copper clad PCB blanks,) and the quality can be judged using an inexpensive 100X Optical Zoom Microscope XFox Mobile Phone Microscope ...", IBC X000WGY25R, and a cell phone for the camera, and, evaluating the print resolution for various methods of constructing the print files from the CAE/CAD software.

The following generalized procedure used is as follows:

1. From within pcb(1):
   1. File->Export layout...->ps
      1. check drill-helper
      2. uncheck auto-mirror
      3. check ps-invert, (only for negative layout)
      4. check multi-file
2. From within gerbv(1):
   1. In pcb(1), File->Export layout...->gerber
   2. In gerbv(1):
      1. View->Rendering->High Quality
      2. View->Change background color->Color name: #FFFFFF
      3. Layer->Change color->Color name: #000000
      4. Layer->Change color->Opacity: 255
      5. Layer->Invert color, (only for negative layout)
      6. File->Export->PDF...
      7. File->Export->Postscript...

The file name used below by the first method is "10x10.bottom.ps", and the file name used below by the second method is "10x10.bottom.1.ps" and "10x10.bottom.pdf". These were made for comparative purposes.

The gimp(1) program was used for printing the files to the printer:

1. Import->Resolution: 1440
2. File->Print...
3. Image->Settings->Center: None
4. Image Quality: Diffusion
5. Color: Color Mode: None
6. Color: Color Enhancement: Off
7. Advanced->Media Type: InkJet Paper
8. Advanced->Slow Drying Paper: Off
9. Advanced->Print Quality: Best
10. Advanced->Color/Greyscale: Greyscale
11. Advanced->Paper Thickness: Regular
12. Advanced->Bi-Directional Printing: On

Figure II is from a Xerox C560, transparency Xerox 3R3108, at Staples. The file name is "10x10.bottom.pdf", 340784 bytes, as seen by exposure light, (the foil image is printed on the other side of the film, which would be next to the copper.)

Figure III is from a Xerox C560, transparency Xerox 3R3108, at Staples. The file name is "10x10.bottom.pdf", 340784 bytes, as seen by exposure light, (the foil image is printed on the other side of the film, which would be next to the copper.)

Figure IV is from a Xerox C560, transparency Xerox 3R3108, at Staples. The file name is "10x10.bottom.pdf", 340784 bytes, as seen by exposure light, (the foil image is printed on the other side of the film, which would be next to the copper.)

Note the narrow spacing in the long lines. This was visible as fringing to the naked eye.

Figure V is from a Brother MFCJ870DW Color Inkjet, transparency Strathmore 598030 Inkjet Translucent Vellum, IBC 1201759803. The file name printed is "10x10.bottom.ps", 17933 bytes, as seen by the exposure light, (the ink is on the other side of the film, and would be next to the copper.)

Figure VI is from a Brother MFCJ870DW Color Inkjet, transparency Strathmore 598030 Inkjet Translucent Vellum, IBC 1201759803. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, (i.e., Figure V with the film turned over.)

Figure VII is from a Brother MFCJ870DW Color Inkjet, transparency Strathmore 598030 Inkjet Translucent Vellum, IBC 1201759803. The file name printed is "10x10.bottom.2.ps", 17933 bytes, as would be next to the copper, (i.e., Figure V with the film turned over,) is the same as Figure VI, above, but the Postscript file was produced from gerbv(1), and the Gimp->Advanced->Media Type: Transparency was used in the print command for Gimp.

Figure VIII is from a Brother MFCJ870DW Color Inkjet, transparency transparency "Grafix Inkjet Film Matte, IBC 9670114402. The file name printed is "10x10.bottom.ps", 17933 bytes, as seen by the exposure light, (the ink is on the other side of the film, and would be next to the copper.)

Figure IX is from a Brother MFCJ870DW Color Inkjet, transparency Grafix Inkjet Film Matte, IBC 9670114402. The file name printed is "10x10.bottom.ps", 17933 bytes, and would be next to the copper, (i.e., Figure VIII with the film turned over.)

Figure X is from a Brother MFCJ870DW Color Inkjet, transparency Grafix Inkjet Film Matte, IBC 9670114402. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, (i.e., Figure VIII with the film turned over.)

Figure XI is from a Brother MFCJ870DW Color Inkjet, transparency Grafix Inkjet Film Matte, IBC 9670114402. The file name printed is "10x10.bottom.2.ps", 157068 bytes, and would be next to the copper, (i.e., Figure VIII with the film turned over,) and is the same as Figure IX, above, but the Postscript file was produced from gerbv(1), and the Gimp->Advanced->Media Type: Transparency was used in the print command for Gimp.

Figure XII is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 10x10.bottom.ps

Figure XIII is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 10x10.bottom.ps

Note the narrow spacing in the lines. This was visible as fringing to the naked eye.

Figure XIV is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 10x10.bottom.ps

Note the narrow spacing in the lines. This was visible as fringing to the naked eye.

Figure XV is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 10x10.bottom.ps

Note the narrow spacing in the lines. This was visible as fringing to the naked eye.

Figure XVI is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "10x10.bottom.3.ps", (a remake from gerbv(1),) 157068 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 10x10.bottom.3.ps

Note the "jog" in the lines.

Figure XVII is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "10x10.bottom.3.ps", (a remake from gerbv(1),) 157068 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 10x10.bottom.3.ps

Note the narrow spacing in the lines. This was visible as fringing to the naked eye.

Figure XVIII is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "10x10.bottom.3.ps", (a remake from gerbv(1),) 157068 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 10x10.bottom.3.ps

Note the narrow spacing in the lines. This was visible as fringing to the naked eye.

Figure XIX is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "15x15.bottom.ps", 15213 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 15x15.bottom.ps

Figure XX is from a Brother MFCJ870DW Color Inkjet, transparency 3M CG 3480, (which is recommended in the Brother MFCJ870DW documentation,) purchased on EBay. The file name printed is "15x15.bottom.ps", 15213 bytes, as would be next to the copper. Gimp(1) was not used:

1. The paper type was set to Transparency on the printer.
2. LPDEST=MFCJ870DW
3. PRINTER=MFCJ870DW
4. export LPDEST PRINTER
5. lp 15x15.bottom.ps

Figure XXI is from a Brother HL-2270DW Laser Printer, transparency Strathmore Laser Translucent Vellum. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lp 10x10.bottom.ps

Figure XXII is from a Brother HL-2270DW Laser Printer, transparency Strathmore Laser Translucent Vellum. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lp 10x10.bottom.ps

Figure XXIII is from a Brother HL-2270DW Laser Printer, transparency Strathmore Laser Translucent Vellum. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lp 10x10.bottom.ps

Figure XXIV is from a Brother HL-2270DW Laser Printer, transparency Strathmore Laser Translucent Vellum. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lp 10x10.bottom.ps

Figure XXV is from a Brother HL-2270DW laser printer, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr -o media=Letter,Transparency 10x10.bottom.ps

Note that transparencies are not mentioned as a supported media in any of the Brother US manuals for the HL-2270DW, but are in the Canadian version specifications section. (This is mentioned since the Brother laser printers are suspected of subjecting the media to a higher temperature than other printers-but the Brother manuals claim the fusing temperature is 200C = 392F, which is typical of almost all laser printers.) Brother USA was contacted for resolution and replied "Transparency paper is not supported on the machine and should not be used." (There is an associated issue in that 3M is going out of the transparency business, also. See: Product Discontinuation.) Reader discretion is advised.

Figure XXVI is from a Brother HL-2270DW laser printer, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr -o media=Letter,Transparency 10x10.bottom.ps

Note that transparencies are not mentioned as a supported media in any of the Brother US manuals for the HL-2270DW, but are in the Canadian version specifications section. (This is mentioned since the Brother laser printers are suspected of subjecting the media to a higher temperature than other printers-but the Brother manuals claim the fusing temperature is 200C = 392F, which is typical of almost all laser printers.) Brother USA was contacted for resolution and replied "Transparency paper is not supported on the machine and should not be used." (There is an associated issue in that 3M is going out of the transparency business, also. See: Product Discontinuation.) Reader discretion is advised.

Figure XXVII is from a Brother HL-2270DW laser printer, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr -o media=Letter,Transparency 10x10.bottom.ps

A cursory analysis of the lines in Figure XXVII Indicate that the Brother HL-2270DW laser printer with a transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009, is capable of producing 10 mil lines with 10 mil spacing, with an accuracy of +/- 10%, or +/- 1 mil. (The diameter of the window is about 9 10 mil spaces, or 0.09 inches.)

As a crude approximation, the total length of each run in Figure I is about 20 feet = 240 inches. 240 / 0.09 = 2667, (1 in 2667 is about 3.37 sigma,) and assuming a standard deviation of 1 mil in 0.09 inches, or one 3.37 mil width error should occur in the 20 feet-just due to lithography, (not including alignment errors in the printer, dirt, etc; just the lithography, as a crude approximation.)

Note that Figure I is not a realistic circuit-it is all interconnect, with no components or vias; it is a worst case scenario for line width accuracy. The specification, (based on this crude approximation, with a totally inadequate number of samples-not to mention analytical equipment,) is that the maximum line width deviation of a 10 mil run on a 4 inch by 3 inch PC board would be about +/- 30%, which would be acceptable for realistic DIY handmade circuits.

Note that transparencies are not mentioned as a supported media in any of the Brother US manuals for the HL-2270DW, but are in the Canadian version specifications section. (This is mentioned since the Brother laser printers are suspected of subjecting the media to a higher temperature than other printers-but the Brother manuals claim the fusing temperature is 200C = 392F, which is typical of almost all laser printers.) Brother USA was contacted for resolution and replied "Transparency paper is not supported on the machine and should not be used." (There is an associated issue in that 3M is going out of the transparency business, also. See: Product Discontinuation.) Reader discretion is advised.

Figure XXVIII is from a Brother HL-2270DW laser printer, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr -o media=Letter,Transparency 10x10.bottom.ps

Note that transparencies are not mentioned as a supported media in any of the Brother US manuals for the HL-2270DW, but are in the Canadian version specifications section. (This is mentioned since the Brother laser printers are suspected of subjecting the media to a higher temperature than other printers-but the Brother manuals claim the fusing temperature is 200C = 392F, which is typical of almost all laser printers.) Brother USA was contacted for resolution and replied "Transparency paper is not supported on the machine and should not be used." (There is an associated issue in that 3M is going out of the transparency business, also. See: Product Discontinuation.) Reader discretion is advised.

Figure XXIX is from a Brother HL-2270DW laser printer, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr -o media=Letter,Transparency 10x10.bottom.ps

Note that transparencies are not mentioned as a supported media in any of the Brother US manuals for the HL-2270DW, but are in the Canadian version specifications section. (This is mentioned since the Brother laser printers are suspected of subjecting the media to a higher temperature than other printers-but the Brother manuals claim the fusing temperature is 200C = 392F, which is typical of almost all laser printers.) Brother USA was contacted for resolution and replied "Transparency paper is not supported on the machine and should not be used." (There is an associated issue in that 3M is going out of the transparency business, also. See: Product Discontinuation.) Reader discretion is advised.

Figure XXX is from a Brother HL-2270DW laser printer, transparency Strathmore Laser Translucent Vellum, IBC 1201759854. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr 10x10.bottom.ps

Figure XXXI is from a Brother HL-2270DW laser printer, transparency Strathmore Laser Translucent Vellum, IBC 1201759854. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr 10x10.bottom.ps

Figure XXXII is from a Brother HL-2270DW laser printer, transparency Strathmore Laser Translucent Vellum, IBC 1201759854. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr -P BrGenML1 -o media=Letter,1200dpi,THICK 10x10.bottom.ps

The parameters were found by:

1. lpoptions -l

Figure XXXIII is from a Brother HL-2270DW laser printer, transparency Strathmore Laser Translucent Vellum, IBC 1201759854. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr -P BrGenML1 -o media=Letter,1200dpi,THICK 10x10.bottom.ps

Compare the series of microphotographs around Figure XXVII, above, (Brother HL-2270DW laser printer, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060),) with the series around Figure XXXIII, immediately above, (Brother HL-2270DW laser printer, Strathmore Laser Translucent Vellum,) which has almost the same line resolution, and is comparable if it has adequate UV translucency, (which is YTBD.) Vellum products are used by many due to availability issues for translucent foil transparencies-particularly in Asia and Europe.

Figure XXXIV is from a Brother HL-2270DW laser printer, transparency Strathmore Laser Translucent Vellum, IBC 1201759854. The file name printed is "10x10.bottom.ps", 17933 bytes, as would be next to the copper, and was printed using lp(1):

1. lpr -P BrGenML1 -o media=Letter,1200dpi,THICK 10x10.bottom.ps

Figure XXXV is from an unknown brand laser printer at Kinkos/FedeX which had a transparency option, transparency 3M CG 3480, purchased on EBay. The file name printed is "10x10.bottom.ps", 17933 bytes, converted to PDF format with ps2pdf(1), (the laser printer would not print Postcript files,) as would be next to the copper.

Figure XXXVI is from an unknown brand laser printer at Kinkos/FedeX which had a transparency option, transparency 3M CG 3480, purchased on EBay. The file name printed is "10x10.bottom.ps", 17933 bytes, converted to PDF format with ps2pdf(1), (the laser printer would not print Postcript files,) as would be next to the copper.

Figure XXXVII is from an unknown brand laser printer at Kinkos/FedeX which had a transparency option, transparency 3M CG 3480, purchased on EBay. The file name printed is "10x10.bottom.ps", 17933 bytes, converted to PDF format with ps2pdf(1), (the laser printer would not print Postcript files,) as would be next to the copper.

Figure XXXVIII is from an unknown brand laser printer at Kinkos/FedeX which had a transparency option, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009. The file name printed is "10x10.bottom.ps", 17933 bytes, converted to PDF format with ps2pdf(1), (the laser printer would not print Postcript files,) as would be next to the copper.

Figure XXXIX is from an unknown brand laser printer at Kinkos/FedeX which had a transparency option, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009. The file name printed is "10x10.bottom.ps", 17933 bytes, converted to PDF format with ps2pdf(1), (the laser printer would not print Postcript files,) as would be next to the copper.

Figure XXXX is from an unknown brand laser printer at Kinkos/FedeX which had a transparency option, transparency Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009. The file name printed is "10x10.bottom.ps", 17933 bytes, converted to PDF format with ps2pdf(1), (the laser printer would not print Postcript files,) as would be next to the copper.

Conclusion on Photolithography

Transparency support is disappearing from home laser printers, and availability of transparency film is declining. However, the Apollo Laser Jet Printer and Copier Transparency Film, 50 Sheets (CG3060), IBC 1857509009, film performed the best on commercial laser printers at print shops/office supply stores, and is the preferred printing method and media-as long as it is available.

The Strathmore Laser Translucent Vellum performed well, and produced almost the same quality as transparency films printed on commercial laser printers at print shops when printed on a home laser printer without a transparency option-and is the preferred method for quick-turn projects. The UV translucency is untested at this time.

The lp(1) and rlp(1) commands in Linux, (using the standard cups(1) drivers,) are the preferred printing method for transparencies on home laser printers, i.e., gimp(1) should not be used, (gutenprint(1) was not available for evaluation.)

Ink jet printers are probably not recommended for making transparencies of the resolution required for PCBs. (3M CG 3480 transparencies performed the best, but it is doubtful consistent 10 mil copper and 10 mil spacing could be sustained-and its doubtful how much longer 3M CG 3480 media will be available.) (The Epson line of printers utilize electrostatic control of the ink, supposedly better, but was not available for evaluation.)

License

A license is hereby granted to reproduce this design for personal, non-commercial use.

THIS DESIGN IS PROVIDED "AS IS". THE AUTHOR PROVIDES NO WARRANTIES WHATSOEVER, EXPRESSED OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY, TITLE, OR FITNESS FOR ANY PARTICULAR PURPOSE. THE AUTHOR DOES NOT WARRANT THAT USE OF THIS DESIGN DOES NOT INFRINGE THE INTELLECTUAL PROPERTY RIGHTS OF ANY THIRD PARTY IN ANY COUNTRY.

So there.

Copyright © 1992-2016, John Conover, All Rights Reserved.

Comments and/or problem reports should be addressed to:

john@email.johncon.com

http://www.johncon.com/john/

http://www.johncon.com/ntropix/

http://www.johncon.com/ndustrix/

http://www.johncon.com/nformatix/

http://www.johncon.com/ndex/